If you are thinking about growing heirloom varieties next season, you can do no better than get hold of the Plants of Distinction "Simply Vegetables" seed brochure 2012. They also have a website with a very good online selection: http://www.plantsofdistinction.co.uk/acatalog/A-Z_of_Vegetables_TOMATO.html
I would suggest that if you are new to growing tomatoes that you include a cherry variety in your selection as these are usually the easiest and most likely to produce a successful harvest.
Large varieties usually produce a limited yield and take longer to grow - in a poor summer they could run out of steam before they mature and ripen. My favourite large variety is Oregon Spring which is a bush variety and will grow well outdoors in a sheltered position.